いい (ii): A very ‘good’ Japanese word

The Japanese word いい (also 良い or よい), roughly translated as “good,” has a variety of uses making it a “good” word indeed. It can be used to mean something that is morally “good,” of good quality, or sufficient in some way. In this post I’ll go through a bunch of ways to use this word and some related topics.

Let’s start with a simple usage:

この映画、いいね。

This movie is good.

Here it simply means the movie is “good”, in the sense that it is enjoyable, thought-provoking, emotional, etc.

There are some expressions where a noun is used with “~がいい” and have a set meaning. For example:

僕の弟は頭がいいよ

My brother is really smart. (lit. “My brother has a good head”)

Another expression is 顔立ちがいい which means someone is good looking (literally, “has good facial features”).

“~したほうがいい” is a very useful expression that means it is “Better to do ~” and is used when strongly suggesting something.

日本語を毎日勉強したほうがいいと思う

I think it’s best to study Japanese every day.

“~するといい” is a similar expression that is a little weaker than “~したほうがいい,” and is used like this:

映画館に少し早めに行くといいかもしれないね。

It might be better to go to the movie theater a little early.

いい can also be used with words that describe ability, to mean someone is “good” (skillful) at them. Take for example 記憶力, which means “memory” (as an ability).

記憶力がよくないとお医者さんになれないよ

If you don’t have a good memory, you can’t become a doctor.

The opposite of いい in this case is よくない or わるい (bad).

年をとると記憶力が悪くなるよね。

As you get older, your memory gets worse.

いい can also be used in the form “~して（も）いい(ですか）？”to ask permission for something, as in “is it OK to do~?”.

先生、僕もう帰っていいですか？

Teacher, is it OK for me to go home now?

Note that this has a different connotation than “帰れる？” (or “帰ることができる?”) which means “Is it possible to go home?”. “していい?” doesn’t have anything to do with possibility, but rather permission or moral correctness of something.

The opposite here, in the sense of something morally right or wrong, would be いけない. You can use this word in the ”〜してはいけない” for to show something is wrong or not allowed.

日本の本屋では、立ち読みしてはいけないです。

In Japanese bookstores, standing and reading books is not permitted.

(A more succinct way to say this is “立ち読み禁止”, and you may see this on signs posted around bookstores in Japan)

You can replace いけない with だめ or ならない without a significant change in meaning.

Another common usage is using いい to mean “no thanks”, as when turning down something offered.

Waiter: 他に何かお飲みになりますか?

Waiter: Would you like something else to drink? (polite language)

Customer: いいえ、僕はいいです。

No thanks, I’m OK.

This can be abbreviated as just “いいです”, and can be a little confusing because it seems to contrast with the typical meaning of “good” as discussed above. But if you think of the English expression “I’m good” which is also used when refusing something, it’s easy to remember. By the way, when saying this phrase, you can put out your hand, palm outward, and wave it slightly back and forth.

Other ways to turn down something offered would be ”結構です” or “いらない”, the latter being less polite and more casual.

If, on the other hand, you wanted to have a drink (say, a beer), you could say ”ビールお願いします” .

One thing you should be careful of is that there are cases when English “good” doesn’t always translate well to いい. One of those is when “good” is used to mean “tasty” when talking about food. In cases like these, you can say おいしい or うまい (the formal being more polite) instead.

このバナナ、おいしいね！

This banana is good!

The past tense of いい is よかった. While this literally means “was good”, it is used as a set expression to refer to being glad that something happened.

Person A: 友達の赤ちゃんが無事に生まれたみたいだよ

Person A: It seems like my friend’s baby was born without any problems.

Person B: よかった！

Person B: That’s great!

A final expression is ”いいから”, which is used when you want someone to forget about something else and listen to what you are saying. It’s literal meaning is “because (it’s) good”.